Systems and methods for detection of cells using engineered transduction particles

Abstract

Systems and methods for detecting and/or identifying target cells (e.g., bacteria) using engineered transduction particles are described herein. In some embodiments, a method includes mixing a quantity of transduction particles within a sample. The transduction particles are associated with a target cell. The transduction particles are non-replicative, and are engineered to include a nucleic acid molecule formulated to cause the target cell to produce a series of reporter molecules. The sample and the transduction particles are maintained to express the series of the reporter molecules when target cell is present in the sample. A signal associated with a quantity of the reporter molecules is received. In some embodiments, a magnitude of the signal is independent from a quantity of the transduction particle above a predetermined quantity.

What is claimed is: 
     
         1 . A method of detecting the presence of a target cell within a biological sample using an instrument, comprising:
 mixing a plurality of transduction particles associated with the target cell with the biological sample, the plurality of transduction particles engineered to be non-replicative and to include a nucleic acid molecule formulated to cause the target cell to produce a plurality of reporter molecules, the plurality of transduction particles formulated to bind to and deliver the nucleic acid molecule into the target cell;   maintaining, after the mixing, the biological sample and the plurality of transduction particles for a time period to allow the plurality of reporter molecules to be produced within the biological sample when the target cell is present in the biological sample;   placing a reaction chamber containing the biological sample in optical communication with a detector of the instrument;   conveying, via a delivery member, a reagent into the reaction chamber, the reagent formulated to react with the plurality of reporter molecules to catalyze production of a signal associated with a quantity of the plurality of the reporter molecules, the reagent being conveyed via the delivery member at an angle and in a direction nonperpendicular to a surface of the biological sample within the reaction chamber; and   receiving, via the detector of the instrument, the signal associated with the quantity of the plurality of reporter molecules.   
     
     
         2 . The method of  claim 1 , wherein the angle at which the reagent is conveyed is between 15 and 45 degrees relative to a longitudinal axis of the reaction chamber. 
     
     
         3 . The method of  claim 1 , wherein the conveying the reagent is performed such that the reagent is further conveyed with a swirling motion into the reaction chamber. 
     
     
         4 . The method of  claim 1 , wherein the conveying includes conveying the reagent at a flow rate of at least one milliliter per second. 
     
     
         5 . The method of  claim 1 , wherein the conveying includes moving a plunger in a plunger direction within a reagent volume, a first end portion of the delivery member disposed within the reagent volume, a second end portion of the delivery member disposed within the reaction chamber, a flow of the reagent exiting the second end portion of the delivery member in an exit direction nonparallel to the plunger direction. 
     
     
         6 . The method of  claim 1 , further comprising:
 maintaining a position of the reaction chamber relative to the detector between the conveying and the receiving.   
     
     
         7 . The method of  claim 6 , wherein the maintaining the position includes limiting at least one of lateral or vertical motion of the reaction chamber. 
     
     
         8 . The method of  claim 1 , further comprising:
 maintaining a distance between reaction chamber and the detector of the instrument during the receiving.   
     
     
         9 . The method of  claim 1 , wherein:
 the reporter molecule is any one of a bacterial luciferase, an eukaryotic luciferase, a fluorescent protein, an enzyme suitable for colorimetric detection, a protein suitable for immunodetection, a peptide suitable for immunodetection or a nucleic acid that function as an apatamer or that exhibits enzymatic activity; and   the reagent includes tridecanal.   
     
     
         10 . The method of  claim 1 , wherein the receiving is performed for less than sixty seconds after the conveying. 
     
     
         11 . The method of  claim 1 , wherein:
 the sample is a raw sample that has not undergone a separation operation or a washing operation; and   the target cell within the sample is non-isolated.   
     
     
         12 . The method of  claim 1 , wherein:
 the signal is a light emission associated with a flash luminescence reaction; and   the reagent comprises a fatty aldehyde formulated to catalyze the luminescence reaction.   
     
     
         13 . The method of  claim 1 , wherein:
 the reaction chamber includes a flat base; and   the placing includes putting the biological sample in optical communication with the detector of the instrument via the flat base.   
     
     
         14 . A method of detecting the presence of a target cell within a biological sample using an instrument, comprising:
 placing a reaction chamber containing a sample in optical communication with a detector of the instrument, the biological sample containing a plurality of reporter molecules;   conveying, via a delivery member, a reagent into the reaction chamber at an angle relative to a longitudinal axis of the reaction chamber, the reagent formulated to react with the plurality of reporter molecules to enhance the production of a signal associated with a quantity of the plurality of the reporter molecules; and   receiving, via the detector of the instrument, the signal associated with the quantity of the plurality of reporter molecules.   
     
     
         15 . The method of  claim 14 , wherein the conveying the reagent is performed such that the reagent is further conveyed with a swirling motion into the reaction chamber. 
     
     
         16 . The method of  claim 14 , wherein the conveying includes conveying the reagent at a flow rate of at least one milliliter per second. 
     
     
         17 . The method of  claim 14 , wherein the delivery member is positioned such that the conveying the reagent produces a circumferential flow of the reagent. 
     
     
         18 . The method of  claim 14 , further comprising
 maintaining a distance between reaction chamber and the detector of the instrument during the receiving.   
     
     
         19 . The method of  claim 14 , wherein:
 the signal is a light emission associated with a flash luminescence reaction; and   the reagent comprises a fatty aldehyde formulated to catalyze the luminescence reaction.   
     
     
         20 . The method of  claim 14 , wherein:
 the reaction chamber includes a flat base; and   the placing includes putting the biological sample in optical communication with the detector of the instrument via the flat base.